Derby took to his new legs almost immediately. Photo: Buster Hein/Cult of Mac

Derby the dog has a birth defect that renders his front legs mostly useless. After his original owners surrendered him, animal-rescue organization Peace and Paws took him in, and that’s where he caught the attention of Tara Anderson.

Anderson is the director of CJP product management for 3D Systems, a company that specializes in 3-D printing and prototyping, and when a cart didn’t work well enough for the dog’s needs, Derby received some custom-made, 3D-printed prosthetics. The team decided that spring-like “running man” limbs would get stuck in the ground, so Derby’s new legs are rounded for maximum mobility and comfort.

Friends sometimes tell me I have a hollow leg, but they don’t really mean it: they just mean that my rampant alcoholism is frequently imperceptible. If it were literally true that I had a hollow leg, I’d probably be tempted to do something crazy with it… like, say, run an Apple Dock Connector up through it and turn my upper calf into an easily accessible iPhone dock.

That’s why I’m so green with envy reading this Telegraph story about Trevor Prideaux, a British man born without a left arm who modified his prosthetic to be a smartphone dock. The only problem? He crammed a Nokia in there, not an iPhone!